1. Field of the Invention
The invention relates to a coating composition, more particularly to a curable coating composition. This invention also relates to a method for making a coated metal plate having an embossment-like texture formed from the coating composition, and to a coated metal plate having an embossment-like texture made by the method.
2. Description of the Related Art
There are two conventional methods for making a metal plate or roll having embossed patterns, which are stereo-patterns recognizable by the naked eye. One of the conventional methods includes the steps of applying to a metal plate a coating of thermoplastic polyvinyl chloride (PVC) in a thickness of about 200 um, hot-pressing the coating by using an embossing roller, and quenching the coated metal to form an embossed pattern on the metal plate. However, the aforesaid conventional method has the following disadvantages:
1) The PVC coating typically includes a plasticizer, such as dioctyl phthalate or tricresyl phosphate, which is prone to migration and hence environmental pollution. The use of the plasticizer is likely to be regulated in the very near future.
2) In order to conduct the hot pressing, the coating should be as thick as 200 um, which in turn increases the production costs.
3) The embossed pattern of the coating is liable to vanish when subjected to heat or stress. Furthermore, when the coated metal plate product is used outdoors, the coating is liable to degrade due to light and heat. Therefore, the metal plate product is not useful at high temperatures.
The other one of the conventional methods includes the steps of gluing an embossed and patterned PVC sheet to a metal substrate, and pressing the PVC sheet against the metal substrate to make a metal plate or roll having embossments. Since polyvinyl chloride is also used in this method, the aforesaid disadvantages are also encountered. Additionally, since a series of steps are required to adhere the PVC sheet to the metal substrate, production is relatively complicated and expensive. Furthermore, the PVC sheet is monotonous in color so that the appearance of the product has limited variety.